Drugs Affecting the GI Tract Flashcards
(37 cards)
What is GORD?
gastro oesophageal reflux disease
What effects does GORD have?
- oesophagitis
- stricture
- Barrett’s metaplasia
- oesophageal -adenocarcinoma
How do you treat GORD?
- suppress the acid
- use proton pump inhibitors (omeprezole)
- H2 blockers (Ranitidine)
- antacids (increase PH)
- alginates (Gaviscon)
How do alginates work?
- alginate can bind calcium, when this happens to becomes rigid like a thick gel
- bicarbonate in the alginate reacts with the acid to form carbon dioxide and water.
- The CO2 formed gets trapped inside the gel making it more buoyant so it floats to the surface
- a barrier is formed which prevents acid refluxing into the oesophagus
What causes stomach ulceration?
helicobacter pylori
In what ways does helicobacter pylori damage the stomach?
- acid production
- barrer damage
What can Helicobacter Pylori cause?
- gastritis
- gastric and duodenal ulcers
- gastric cancer (class 1 carcinogen)
How can Helicobacter pylori cause damage in such acidic conditions?
- flagella so motile
- expresses enzymes that allow it to colonise close to the epithelium like mucinase which breaks down mucin on the surface of the epithelium
- adhesion receptors not the surface allow it to anchor on
- urease converts urea into an ammonium ion and a bicarbonate ion
- ammonium ion causes inflammation
- bicarbonate ion allows it to neutralise its local environment
What does Hp in the antrum cause?
- G cells to hyper secrete gastrin
- decrease astral D cell somostatin release
- leads to hypergastrinaemia and duodenal ulcers]
What does Hp infection of the corpus lead to?
-reduced acid secretion and hypochlorhydria
associated with gastric ulcers
How are hypergastrinaemia and hypoclorhydria treated?
triple therapy consisting of antibiotics amoxicillin, clarithromycin and a proton pump inhibitor
What is creon?
a prescription medicine used to treat EPI e.g where the pancreas does not make enough enzymes (e.g chronic pancreatitis)
-replaces enzymes that the pancreas isn’t producing, helping you digest fats, proteins and carbohydrates
Why is creon given in a delayed release capsule?
so that the enzymes are not released until they are needed in the small intestine
How do aminosalicylates work in treating IBD?
- work as a scavenger of oxygen free radicals (reducing inflammation)
- blocks production and chemotaxis of leukotrienes
- many other actions aimed at modifying the immune response and inflammation
What is an example of an immunomodulator?
azathioprine
How does azathioprine work?
interferes with DNA synthesis and inhibits proliferation of rapidly dividing cells
What is a biologic?
a monoclonal antibody against TNF-α
What is TNF-α?
- an inflammatory cytokine involved in host defence, inflammation, apoptosis and activation of immune cell functions
- in increase in its expression is related to IBD
What at some examples of biologics and how do they work?
infliximab, adalimumbab and golimumab
act as monoclonal antibody against TNF-α
How can you prevent the initiation/ maintenance of inflammation mediated by adhesion molecules in IBD?
- use inhibitors to molecules involved in lymphocyte migration and recruitment within the intestinal mucosa as this causes inflammation
- inhibitors to these molecules interfere with adhesion interactions of endothelial cells and circulating immune cells
What is an example of one of these inhibitors?
Vedolizumab
How do corticosteroids work?
- regulate gene expression
- bind to corticosteroid receptor which suppresses inflammatory processes
How do stimulant laxatives work?
increase motility through chemoreceptor activation and the myenteric nerve plexus
Examples of stimulant laxatives?
- Senna
- cascara
